The first manned aircraft that can fly day and night powered entirely by solar energy will use a "revolutionary" inflatable hangar to replace one damaged in last week's midwest tornadoes.

Powerful storms that hit the St Louis, Missouri area on Friday rendered Solar Impulse's hangar at Lambert-St. Louis International Airport unusable, organisers of its current US flight said.

As it sets out on the third leg of its US flight, a statement said that "to protect the aircraft upon landing ... Solar Impulse will deploy a revolutionary inflatable structure for the first time" when it arrives in Missouri early on Tuesday.

The Solar Impulse project, founded and led by two Swiss pilots, aims to showcase what can be accomplished without fossil fuels, and has set as its "ultimate goal" an around-the-world flight in 2015.

The first leg of Solar Impulse's US tour took place on May 3, when Swiss aviator Bertrand Piccard flew the aircraft from the San Francisco, California area to Phoenix.

On that initial leg, the plane - which has a slim body and four electric engines attached to enormous wings - flew at an average speed of about 49k/ph.

The aircraft set a new distance record on May 23 when it landed after the second leg of a cross-country US tour.

The previous distance record was attained by Solar Impulse one year ago on a 1,116km flight from Switzerland to Spain.

Now, Piccard will take off Monday on a a 21-hour flight - his longest flight in the single-seat cockpit to date. The Solar team will have just a few hours to set up an inflatable hangar to park the plane.

"The stopover in St. Louis during the crossing of the United States is very important and symbolic for Solar Impulse," the organisers said.

St Louis was chosen as the midwest stopover to pay homage to aviation pioneer Charles Lindbergh and his "Spirit of St Louis," the first plane to fly from New York to Paris non-stop.

Energy provided by 12,000 solar cells powered the plane's propellers.

The plane can fly at night by reaching a high elevation of 8,230 metres and then gently gliding downward, using almost no power until the sun comes up to begin recharging the solar cells.